====== Non-repudiation ======
proof of integrity using proof of origin with a high assurance of authenticity.

Hashing data to prove that that a bundle of data is identical to what you're getting. Makes it harder to bundle viruses within data

hashed data should also provide a digital signature (pub/priv key crypto) from the source 

guarantees that the party was involved in the transaction or communication and cannot deny authenticity of their signature